May get a Vibe GT and have a 17" rim question

[computer ninja]

I currently have a 1998 Golf VW GTI VR6, but with GM's new 0/0/0 promotion and my wife working for GM, I may look into getting a Vibe GT just for the "new" car feeling and the 0% interest savings.However, I despise the rims that Pontiac offers on this car and would want to use the rims I have on my car, which are 17" Borbet Type M wheels with Yokohama (shoot, forgot which ones) tires. The tires are 205/40/17. What dimensions are the "stock" 17" tires that come on the Vibe GT, and what type of adjustments would I have to make in terms of the speedometer gear?Also, I believe my wheels are 5x100, so there shouldn't be a fit problem.Thanks for anyone's help.

[NovaResource]

The standard GT wheels are 16" with a 205/55-16 tires (24.9" diameter). The optional wheels are 17" with a 215/50-17 tires (25.5" diameter). Your 205/40-17 tires are only 23.5" in diameter.If you put them on a Vibe that came with the 16" wheels, your speedo will be 5.7% too fast. You speedo will indicate 60 but you will only be traveling 56.6 mph.If you put them on a Vibe that came with the 17" wheels, your speedo will be 7.9% too fast. You speedo will indicate 60 but you will only be traveling 55.3 mph.Either way is not good. Your tires are a little on the small side.

[vibe owner]

You think they really adjust the speedometer for the wheels/tires you buy? I doubt it. Anyone know? My GT with 17's runs a bit faster than the speedometer says, but close enough for government roads...

[NovaResource]

The difference between the 16" wheels and the 17" wheels is 2%. Typical allowable error is usually 1% but I doubt GM changes the gears in the trans for just a 2% difference.

[mu_ohio]

This is purely a guess, but I think they might factor the speed difference since it is a digital speedometer. I do know that the factor is hestitant about upping the 16" to 17" at the dealer.

[rodzombie]

Not sure about the Vibe but on the new silverados the speedo settings can be changed in the ecm (electronic control module) to compinsate for tire size changes and rear end gear changes. Since the vibes use computer monitored transmissions it's possible the factory does set the speedo's to compinsate for tire and wheel size. I don't know if the ecm is programable like the one in the Silverado's either.